Makes sense. The US sold Israel 100 GBU 28 bunker-buster bombs, which indeed have a DU core. Most people assume they were meant for Iran's nuclear sites, but using one against a site close to Damascus is a great way of sending a warning to Iran.

So yeah, a 5,000-pound DU bomb hitting a weapons storage building will generate a pretty nice bang - hence the slightly "nuclear" look about the blast.